This invention relates to aligner sensors used for aligning vehicle wheels, and, in particular, to a sensor lock to maintain the sensor in a level position.
To perform a vehicle wheel alignment, an operator initially mounts sensors to a vehicle's wheels. Typically an adapter or sensor support is mounted to the wheel rim to rotate with the wheel. A shaft extends from the sensor and is received in the adapter to pivotally mount the sensor to the adapter. One of the initial operations the operator performs is to level the sensor. If the sensors are not level, the data produced by the aligner will be incorrect. A level indicator is generally mounted on the sensor housing and the sensor is pivoted until the indicator reads level. A lock is provided to hold the sensor in its level position.
In the past, a rotatable knob has been used which operates a clamp, or caliper brake-type lock, which in turn grasps the support shaft to lock the sensor against pivotal motion with respect to the wheel. However, when the knob is turned, the sensor may be moved slightly out of level, requiring that the clamp be released and the sensor releveled. The knob is typically located on the front of the sensor housing. If the sensor housing accidentally falls, the sensor may fall on the knob, damaging the locking device.
Further, the degree to which the sensor is locked against pivotal motion depends on the tightness to which the knob is turned. If the knob is not tightened sufficiently, the knob may loosen, and the sensor may begin to pivot and come out of level during an alignment procedure. If the operator is unaware of the out of level condition, the alignment data readings produced by the sensors may be incorrect.